$image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), "full" );
echo '<a href="' . $image[0] . '">Link to Full Size</a>';
$image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), "full" );
echo '<a href="' . $image[0] . '">Link to Full Size</a>';